Ludlum Measurements 3100, Manual, Page: 44 / 57

7-3
i. If the vacuum is not held, identify and repair leaks.
7.6.2 Identifying Can Assembly Leaks.
a. Open the front panel of the Model 3100 by loosening the four latches.
b. Loosen an air hose fitting from the desiccant switch. See Figure 7-1.
c. Apply grease to the front-panel gasket as required.
d. Close the front panel by securing all four latches lightly.
e. Attach the handheld air pump (electronic pump such as the one in the Model 3100 may be used with
caution) to the OUT port located under the air filter. See Figure 7-2.
f. Plug the IN port.
g. Apply air pressure.
h. Water test options:
(1)
Dunk the unit under water while applying pressure in order to locate air bubbles.
(2) Spray the unit with soapy water/bubbles while applying pressure to identify leaks.
Note: The desiccant door will likely leak when applying pressure above 1 psi. Continue to look for other leaks.
7.6.3 Air Circuit Leak Test.
a. Open the front panel of the Model 3100 by loosening the four latches.
b. Ensure all air hoses are properly connected.
Note: The desiccant switch hoses may have been loosened during the Model 3100 can leak test.
c. While the front panel is open, attach the vacuum pump to the OUT port located under the air filter. See
Figure 7-2.
d. Plug the IN port. See Figure 7-2.
e. Apply a vacuum of -5 inches Hg.
f. Verify that the vacuum is holding before proceeding.
g. If the vacuum will not hold, identify and repair the leak. Repeat the air circuit leak test before proceeding.